Observations on Long Bone Medullary Pressures in Relation to Arterial Po₂, PCO₂ and pH in the Anaesthetized Dog

Abstract

To investigate the influence of variations in arterial oxygen tensions (PaO₂), arterial carbon dioxide tensions (PaCO₂), and arterial pH on long bone medullary pressures, seven anaesthetized dogs were investigated.

Hyperoxia, hypocapnia, hypercapnia or metabolic acidosis had no effect on medullary pressures in any of the regions studied.

Comparing the control medullary pressures, i.e. the mean medullary pressures obtained at the normal range of PaO₂ (75–110 mmHg) with the mean medullary pressures corresponding to the range of PaO₂ of < 75 mmHg, statistically significant (P < 0.05) decreases were seen in both epiphyseal, metaphyseal and diaphyseal medullary pressures, from 27.6 ± 5.0 to 15.5 ± 3.6 mmHg, from 23.5 ± 2.9 to 13.9 ± 2.3 mmHg and from 27.7 ± 3.9 to 18.3 ± 2.5 mmHg (all mean values ± s.e. mean), respectively.

Key Words:

• aetiology
• blood supply
• bone
• femur head
• osteoarthritis
• physiology
• regional blood flow